Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Such standards dictate the type of communication, type of encoding, type of modulation, channel access protocols, intercommunication between components of a wireless communication device, etc. The specifying of intercommunications between components, such as digital signal processors and radio transceivers, primarily limits the data exchanged between such components to standard compliant data. Thus, the standardization of wireless communications enables multiple manufacturers equipment to interoperation with each others equipment, which helps reduce the cost of wireless communications, the standards leave little room for optimization of inter-component performance.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, et cetera, communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channel pair (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system) and communicate over that channel. For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication session between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the receiver receives RF signals, removes the RF carrier frequency from the RF signals directly or via one or more intermediate frequency stages, and demodulates the signals in accordance with a particular wireless communication standard to recapture the transmitted data. The transmitter converts data into RF signals by modulating the data in accordance with the particular wireless communication standard and adds an RF carrier to the modulated data directly or in one or more intermediate frequency stages to produce the RF signals.
As the demand for enhanced performance (e.g., reduced interference and/or noise, improved quality of service, compliance with multiple standards, increased broadband applications, et cetera), smaller sizes, lower power consumption, and reduced costs increases, wireless communication device engineers are faced with a very difficult design challenge to develop such a wireless communication device. Typically, an engineer is forced to compromise one or more of these demands to adequately meet the others. For instance, an engineer may choose a direct conversion topology (i.e., convert directly from an RF signal to a base-band signal or directly from a base-band signal to an RF signal) to meet size requirements and/or broadband application requirements. However, for direct conversion transceivers, DC offset, IQ mismatch, and local oscillation leakage are more detrimental to overall performance.
Costs of manufacturing a radio frequency integrated circuit (IC) may be reduced by switching from one integrated circuit manufacturing process to another. For example, a CMOS process may be used instead of a GaAs, silicon bipolar or bi-CMOS process since it is a more cost affective method of IC manufacture and is typically the technology choice for digital ICs. Such a CMOS process, however, increases temperature and process related variations. As such, noise, gain variation, mismatches and other factors that negatively impact an RF IC performance are increased for a CMOS process. Thus, in many RF IC applications, a designer chooses between cost savings and performance.
Therefore, a need exists for a low power, reduced size, reduced cost, and robust performance radio, radio transmitter, radio receiver, and/or components thereof.